Unified Analysis of Communication Performance Over Composite Fading Channels in Space-Air-Ground Integrated Network

Composite fading channel models have been broadly adopted because of their suitability for channel behaviors of communication systems in the space-air-ground integrated networks (SAGINs). This article provides a unified analysis of communication performance over mixture Gamma (MG) fading channels, which is a general model for the composite fading channel in SAGIN. Reflecting practical degradation factors in communication systems, we consider in-phase/quadrature (I/Q) imbalance and impulsive noise. Most notably, by taking I/Q imbalance and impulsive noise into account, we derive the exact expressions and closed-form approximations for the average symbol error rate of an arbitrary 2-D modulation and those for the average capacity over MG fading channels. Our results are mathematically tractable and have versatility in analyzing the performance of communication systems in SAGIN. Simulation results are given to validate the derived expressions.